1. Field of the Invention
The invention relates to an exhaust nozzle of variable cross-section mounted at the downstream end of a stationary, cross-sectionally circular outlet of a turbojet-engine hot-gas exhaust duct.
2. Discussion of Related Art
Some military aircraft equipped with turbojet engines must carry out missions in subsonic as well as supersonic flight. Such turbojet engines are typically fitted with an after-burner system and with either an axially symmetrical nozzle or substantially two-dimensional exhaust nozzle.
The nozzle must have a variable cross-section if used on afterburner-fitted gas-turbine engines.
In order to gain more thrust at normal full power and at full power with afterburning, a composite nozzle has been developed overtime with converging and diverging variable cross-sections. The kinematics and technology of these converging/diverging nozzles are complex and they are heavy.
In most cases the exhaust nozzle is restricted at its converging portion to allow comparatively simple engineering while achieving satisfactory results.
It is this kind of axially symmetric nozzle which is the object of the present invention.